It’s just under a month before opening night at Radio City Musical Hall, home of the Rockettes, a New York institution since 1932 (though the precision dance troupe first began performing as the “Missouri Rockets” in Saint Louis in 1925). The Rockettes perform for more than a million people during the “Christmas Spectacular” annual eight-week winter run.

The math is staggering: With 195 performances scheduled this season, Radio City sometimes hosts up to five shows a day. Two casts of 40 dancers trade off performances.

In rehearsal, though, they’re all together, in black pants and Rockette tank tops, laughing at jokes even as they hold their arms rigid, frozen in position.

Mike Pont/Getty Images

“Still, be nice and human,” Branam reminds them about their poses. The drummer (rehearsal is accompanied by a kit and piano and, occasionally, sleigh bells) plays a rimshot.

Precision is the Rockettes’ mesmerizing calling card, as iconic and inseparable from the team as their high kicks. Annual auditions draw from a pool of women who must meet two absolute requirements: age (eighteen or older) and height (5’6” to 5’10½”). Rockettes, as a rule, are tall for dancers—ballerinas have an average height just under 5’5.” But the illusion that they are all the same height is accomplished with a bit of theater magic: The tallest stand at the center of their ruler-straight lines, and the dancers are arranged, in descending order, outwards. The tallest take the smallest steps, and the shortest take the biggest.

And the famous kick line, where the Rockettes join arms and throw their legs impossibly high into the air, is more impressive than it seems. Up close, they never touch. As they kick in rehearsal, their arms hover behind each other’s backs. Some dancers keep their hands cupped, others ball theirs into fists.

“It’s your responsibility to hold yourself up,” Branam reminds them.

The rehearsal space is full of medical supplies: rows of colored tape for sore or blistered feet, bottles of hydrogen peroxide, boxes full of cough drops, Tums, hand sanitizer, Pepto Bismol, aspirin, Kleenex, and eye drops. There’s a sign for flu shots on the bulletin board.

Nina Linhart, in her first season as a Rockette, reflects on the physical demands of the show. They inhale bananas and guzzle Powerade: mountains of fruit disappear and fully stocked fridges go empty in the Rockettes’ backstage lounge at Radio City.

Ice baths are “the best thing,” Linhart insists. “At the end of the day we love love love ice baths.”

Elaine Winslow-Redmond remembers how many injuries she saw as a Rockette working in Las Vegas in the 1990s: They were the topic of her graduate thesis in exercise physiology and nutrition at Columbia University. Now the Rockettes’ director of athletic training and wellness, Winslow-Redmond founded the dance company’s athletic training program in 2004, which has drastically reduced the number of injuries—from upwards of 300 to less than 100 per season. She emphasizes prevention as much, if not more, than post-injury care. Strength training is one part, the other is food.

TIMOTHY A. CLARY/AFP/Getty Images

“I really stress the carbohydrates,” she said. Rockettes need the energy: “All of my girls are like quarterbacks in football.”

Each Rockette performs six days a week in almost 100 shows over the course of the season.

“In the morning I always tape my feet, just in case,” Linhart said. The most common complaint, she explains, are blisters: “I had to break in eight new shoes...A lot of the girls have already broken in their shoes,” veteran pairs from previous seasons.

Among the array of footwear the Rockettes put on with each costume change, one is a tap shoe with a hollowed-out heel where a microphone is stored to better catch and amplify the sound of their feet. Until the mic-heeled shoes were specially designed for the troupe in the 1990s, the Rockettes danced to pre-recorded audio of their taps.

Nicole Baker’s first job was being a Rockette, and now she’s in her eleventh season.

“It’s the hardest thing I’ve ever done,” she said, but it’s clearly work she loves: She returns to audition, and perform, every year. Longevity is not uncommon here. Many Rockettes dance into their mid-thirties—and some, like Branam or Winslow-Redmond, even pursue careers in the company beyond.

Still, every Rockette has to prove herself afresh in annual auditions. Over 500 women line up every spring, but just 80 make the cut to perform at Radio City.

For Branam, whose career with the Rockettes began with the 1988 “Christmas Spectacular,” the show and its dancers “keep evolving and getting better,” all while honoring the precision dancing tradition that started with the Rockettes’ founder Russell Markert.

One number, “Parade of the Wooden Soldiers,” remains from that first 1932 show in Radio City, choreographed by Markert with costumes designed by Vincent Minnelli. Though it has no kick line, it’s one of the show’s most stunning routines, with rows of dancers moving with mathematical precision and then collapsing, like dominos, in slow-motion.

“Space is so important,” Baker said of that—and all—the Rockettes’ routines. In rehearsal, a dense network of colored tape marks up the floor: They use a literal grid to finesse their steps.

“What happens off stage is as choreographed as what happens on it,” Linhart added. The dancers have only 78 seconds to change from their soldier costumes to their “New York at Christmas” outfits: shedding pants for plaid coats, tall black hats for short white head bands, red felt cheeks for new shoes and earrings. Each dancer goes to the same spot offstage every time, and shares a dresser with another Rockette in a perfectly calibrated routine.

Mike Pont/Getty Images

On opening night in November, Radio City Music Hall was crowded with adults stirring their prosecco with plastic candy canes and children plucking tufts of cotton candy from sticks while wearing the stiff, elfin souvenir hats that come with them. It’s the Art Deco theater’s 83rd year playing host to this Christmas tradition—in fact, the Rockettes performed at Radio City’s opening night—and they suit each other. The Music Hall glows with holiday spirit.

Though the Rockettes are the indisputable stars of the show, Santa is its narrator. With a mixture of old—“Parade of the Wooden Soldiers,” the annual and opulent final Nativity tableau—and new—a balletic snowflake number, combining “White Christmas” and “Let It Snow”—the “Christmas Spectacular” follows a loose plot, albeit with many detours.

Santa, aided by rows of Rockette reindeers, leaves the North Pole for New York City, where he meets two children, true believer Ben and his skeptical 14-year-old older brother Patrick, at a mall. He demonstrates his special brand of Christmas magic with a small army of Rockette Santas, a genuinely jolly routine full of shaking bellies and ringing bells, and reappears as a Salvation Army Santa outside of a subway station, where he takes them to the North Pole to pick out a present for their little sister—a Raggedy Ann doll, selected amidst a floppy, can-can inspired line of Raggedy-Ann Rockettes.

(Santa, it’s worth noting, has upgraded from a parchment-based list of naughty and nice children to one stored on his tablet.)

Ben and Patrick return home to read the Gospel stories of Christmas together, and the production’s menagerie of animals plod with dignity across the stage: three camels, six sheep, and a single donkey. Even the animals help keep up the tradition—one camel, Ted, has been in the show for more than 20 years. It’s the most calm routine of the night, but its many-layered costumes are the show’s heaviest. Even in apparent repose, the Rockettes are working.

Over the course of 90 minutes, the world falls away, and sometimes even the intervening decades do, too.

Outside, after the show, there’s snow on 6th Avenue: soap bubbles shoot over the sidewalk and street from above the famous neon marquee. Children and adults hold out their hands to catch the wet bits of white as they float down. One little girl collects enough of the faux-snow to build herself a white beard and slick down her hair. Surprise, delight, flit across people’s faces—only now, unlike in the darkened theater, it’s visible.

Like all things to do with the Rockettes, it’s an effect produced by hard work, but with results that feel, and look, like magic.